Tech Paper: Eagle Ford Horizontal Drilling Optimization in Karnes and DeWitt Counties

Optimized drilling methods lead to increased success rate and reductions in rig time

Eagleford-SM-BannerThe drilling of Eagle Ford horizontal wells in Karnes and DeWitt counties traditionally requires at least two bottomhole assembly (BHA) configurations to drill from surface casing to reach total depth (TD). After a few initial successful attempts at drilling from surface casing to TD using a single BHA (one-run), several problems were encountered, resulting in multiple unsuccessful one-run attempts. What began as a study to determine the best bit for one-run applications evolved into a multivariable study to identify the key factors for achieving successful one-run wells.

The success rate of one-run wells increased from 25 to 85% over a seven-month period. Achieving this level of success involved analyzing vertical parameters (specifically through the highly abrasive Wilcox formation), geographic location (correlated with Wilcox formation thickness), motor bend, BHA components, well trajectory, bit selection, and overall well length. Improving the efficiency of drilling Eagle Ford wells with a one-run application proved to be most dependent on the optimization of vertical parameters, Wilcox thickness, and overall well length.

The method and recommendations presented in this paper are most applicable on land. Wells with geologic formations and temperature ranges that can tolerate necessary variations in mud parameters throughout the vertical, curve, and lateral sections should be seriously considered. One-run wells can prove profitable by sacrificing a section rate of penetration (ROP) to gain overall well ROP. For example, a slight reduction of the drilling parameters in the vertical section may reduce the vertical ROP, but will maintain the BHA integrity for the curve and lateral sections, which will result in an increased ROP for the length of the well.

Significant reductions in rig time and the amount of equipment used resulted in an overall increased economic efficiency dependent on time and costs associated with tripping and picking up a new BHA. In addition, eliminating a trip for a new BHA is a simpler operation and, consequently, provides a safer work environment for rig personnel.

Click below to view further details and download the technical paper (PDF).

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Source: Unconventional Resources Technology Conference, 20-22 July, San Antonio, Texas, USA

Authors: Kathryn J. Patton (Halliburton) |  Luke S. Walker (BHP Billiton)

 

One thought on “Tech Paper: Eagle Ford Horizontal Drilling Optimization in Karnes and DeWitt Counties

  1. AvatarYaici Hakim

    Optimization is not just applying some math to identify the most suitable values, it is actually a philosophy of ranking goals; sacrifice a less important parameter, but still crucial, to boost a more important one, optimization is by nature a hard work, evolving and case related, it is compromising, it is the art of defining what matters the most; in the current case achieve one-run operation (bit selection, BHA, mud motor and/or steering technique or technology, drilling parameters and well path, hydraulics, etc.) when considering closely the rig time, mud rheology stability and a huge amount of parameters and factors (geology or tools related or both) should rise the potential to meet success.

    Thank you for sharing.

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